1. Field of the Invention
The invention relates to hairspray compositions, especially those formulated to meet VOC emission standards.
2. The Related Art
Chemically based consumer products have come under ever increasing environmental scrutiny. Spray formulations have been particularly impacted by environmental concerns. Legislation has been enacted to ban chlorofluorocarbons as propellants in aerosol spray compositions. Successor propellants in the form of volatile hydrocarbons have also come under scrutiny. Not only propellants but even solvents such as ethanol are undergoing restriction.
California's legislation concerning volatile organic compounds (VOC) has forced future hairspray products to replace, at least in part, the organic solvent with water. Concentrations of organic propellants present in water-based solvents must also be adjusted to relatively low levels. With such constraints, certain problems have arisen. Water-dispersed systems are slow to dry. Not only do they result in wetness on the hair but there is also an undesirable initial curl droopage due to water being placed on the curl. Quite significantly there is also difficulty in developing the style. Resins formulated in a water-based system can have weak holding power.
A body of literature has developed that attempts to meet these environmental related challenges. Replacement of chlorofluorocarbons with hydrocarbon propellants has been discussed in U.S. Pat. No. 4,859,455 (Nowak, Jr. et al.). Improved tolerance to the hydrocarbon levels was reported as being achieved through neutralization of acrylic resins with mixtures of sodium or potassium hydroxide and certain long chain amines. U.S. Pat. No. 5,021,238 (Martino et al.) reports the further advance of using dimethyl ether (DME) as a hairspray propellant. DME allows use of water as the only solvent thereby significantly reducing the volatiles problem.
Recently there has been disclosed in U.S. Pat. No. 5,068,099 (Sramek) an aerosol hairspray package claiming reduced volatile organic compound emission during the useful life of the package. The spray composition contains a combination of at least two polymers differing in weight average molecular weight by at least 1.5. This blend of polymers combines with a low delivery rate discharge mechanism to provide an atomized composition with mean particle size of at least 60 microns. A significant drawback of this technology is the necessity for very substantial amounts of volatile alcohol; water is present at levels no higher than 10% by weight. Instead of eliminating volatiles from the formula, the patent merely controls the spray emission thereof. Unfortunately, at some point in the life cycle of the package, volatiles will be emitted into the atmosphere.
Even though there have been significant advances in this art, many problems still remain. Some systems are excellent at reducing volatile organic compounds but hair hold, wetness and other physical properties are not equivalent to the old volatile solvent-based formulas. In other instances, physical properties are excellent but there is either insufficient volatiles reduction or the systems are too costly.
Accordingly, it is an object of the present invention to provide a hairspray composition that reduces volatile organic compound emissions to the atmosphere thereby being environmentally friendly.
Another object of the present invention is to provide a hairspray composition which is a water-based system.
A further object of the present invention is to provide a hairspray composition for a water-based system that has improved holding and styling characteristics.
A still further object of the present invention is to provide a hairspray composition for a water-based system that dries fairly quickly and does not impart any undue wet or cool feel to hair or scalp.
These and other objects of the present invention will become more evident from the following summary and detailed description.